The extensive use of coaxial wire in contemporary computer systems has provided the need to develop an inexpensive wire wrap tool capable of accurately wrapping the conductors of coaxial wire around adjacent terminals in the back plane panels commonly employed in computers. System reliability and production efficiency require that each wrap comrpises a proper connection of conductor and terminal. Prior art devices are known that simultaneously wrap multiple conductors around adjacent terminals. These devices have been found to be cumbersome, inefficient, and unsuitable for use with terminals as closely spaced as those in back plane panels.
The prior art devices, as exemplified in U.S. Pat. No. 3,443,606, primarily employ drive shafts rotatably driven by electric or air motors which are interconnected to wrapping bits by means of gear assemblies. The bits of a multiple bit wire wrap tool must be closely spaced because of the close proximity of the terminal pins in the back plane panels employed in present day computers. The closer tolerances require that the gears employed in the gear assemblies of these tools must be of small dimensions. Inherent with the use of these small gears are several disadvantages which make prior art devices unsuitable for use with present day back plane panels. One disadvantage of prior art devices is that gears of small dimension and precise construction are expensive to manufacture and their inclusion in the wire wrap tool inflates the cost. Another disadvantage is that intermeshing the small gears with the rotatable driveshaft results in the wrapping bits being driven at an excessively high rpm, thereby increasing the possibility of broken conductors, cracked insulation and improper wraps resulting from overlapping the turns of the conductors.
The circumferentially rotatable swivel block employed in the present invention obviates the need for gear assemblies and achieves a one to one ratio between rotation of an eccentric driveshaft and rotation of the wrapping bits. This ratio is not obtainable with the gear assemblies of prior art devices.
Another feature of this invention is that upon completion of each wrap the bits are returned to a precise predetermined home position. This feature is important because uniform wraps of multiple conductors around adjacent terminals are obtainable only when the conductor receiving bores in the wrapping ends of the bits are adjacently aligned at the completion of the previous wrap. Prior art devices are not capable of automatically orienting the bits in precise home positions after each wrap because of the high frictional resistances inherent within their gear assemblies.
The present invention is designed to overcome the disadvantages of the prior art devices by providing novel features which accomplish desired advantages.
It is therefore an object of this invention to provide a simple and low cost multiple bit wire wrap tool capable of simultaneously wrapping the conductors of coaxial wire around adjacent terminals.
It is a further object of this invention to provide a multiple bit wire wrap tool wherein the need for gear assemblies is eliminated by providing a simple and efficient drive system to transfer rotation of a drive motor into rotation of wrapping bits. This drive system comprises an eccentric drive shaft cooperating with a circumferentially rotatable swivel block to achieve axial rotation of eccentric wrapping bits received thereon.
Another object of this invention is to provide a multiple wire wrap tool whereby the wrapping bits are returned to a home position upon completion of each wrap.
Still another object of this invention is to provide a multiple bit wire wrap tool whereby high production rates are achieved by reducing the possibility of damage to the conductors during the wrapping process.
It is yet another object of this invention to provide a multiple bit wire wrap tool with which precise and reliable connections will be imparted between the conductors and terminals.